Local thermal spray coating and plasma transferred arc (PTA) cladding services provider Thermaspray is the first company in South Africa to introduce an array of coatings from US-based corrosion, wear and release-coating service provider Plasma Coatings USA – a division of rollers, roller coverings and speciality coatings manufacturer American Roller Company.

Thermaspray added the Plasma Coatings range to its product supply in January.

Thermaspray MD Dr Jan Lourens tells Engineering News that Plasma Coatings’ particular brand of technology combines the advant- ages of thermal spray (metal) coatings with polymer-based top coatings to offer benefits of wear resistance, slip and traction. This was previously unavailable in South Africa, which makes it the first of its kind available in the country.

Product Offering
Plasma Coatings combines the advantages of thermal spray coatings with polymer-based top coatings to offer wear resistance, slip and traction, among other benefits.

The company’s plasma spray system is a dual-coating solution, comprising a base or matrix coating, which is applied as a thermal spray coating, followed by a final layer of polymer. Thermal spray coating is the method of applying materials onto a prepared base material by heating metal particles in the stream of a heat source, creating a semimolten state. Particles are then propelled using a high-velocity speed onto a prepared substrate, where they adhere to the base surface through a mechanical bond.

The base coating is applied using one of four different types of thermally sprayed coating techniques or processes – (1) combustion wire metallising, (2) electric arc, (3) plasma and (4) high-velocity oxygen fuel.

Polymers, meanwhile, are typically available in thicknesses ranging from 0.03 mm to 0.08 mm, and are largely applied through dispersion or electrostatic systems using fluorocarbons, fluoropolymers, silicones, epoxies or teflon industrial coating.

This dual-coating solution can be applied to aluminium, steel, stainless steel, tool steel, copper, ceramics and synthetic materials.

“We identified a distinct gap in the market for this type of combined coating, which saves clients time through reinforcing wear surfaces and achieving consistent performance through improved machine traction, or allowing for zero traction, where necessary,” says Lourens.

He explains that Plasma Coatings’ dual-coating solution can extend the life of a component by up to ten years, reducing costs by as much as 30%.

This leads to a reduced mean time between component replacements which, combined with savings on cleaning materials, for example, will result in a significant increase in savings, uptime and production. Moreover, the easy-to-clean surfaces require less frequent cleaning.

Product Benefits
Lourens notes that the metal base layer of the combined coating provides a hard, durable surface that protects components from wear, owing to mechanical or contact-related forces. When a low coefficient of friction, or zero traction, is required, polymer top coatings are applied to machinery components to reduce the traction and increase the release of the component in its working environment.

A water- and oil-resistant surface is created to prevent materials, such as food ingredients, adhesives or rubber, from sticking, as they slide over components without adhering to it.

However, for applications that require traction, Thermaspray provides a surface-traction coating, which eliminates slippage by combining the unique properties of surface traction and release.

Applicable Industries
Lourens notes that the Plasma Coatings range will benefit a variety of diverse market sectors in South Africa, such as the food processing, packaging, printing, tyre and rubber manufacturing, pulp and paper, as well as plastics industries.

He notes that the product is environment-friendly and Federal Food, Drug and Cosmetic Act-compliant. It can also be used safely in the food processing industry to eliminate the sticking of food ingredients and to prevent corrosion.

In the packaging industry, the dual coating reduces surface adhesion, which accelerates product throughput in chutes, ink pans and hoppers, for instance. Plasma coating will also save time and money for the plastics and tyre manufacturing industries by facilitating the removal of materials from moulds, eliminating the need to reapply mould-release sprays.

The application of plasma coatings will also protect dryer drums, boilers and digesters in the pulp and paper industry from abrasion and erosion.

Lourens notes that, although it takes time to introduce a new product to the market, he is confident that this dual coating will be widely accepted, owing to its many cost- and time-saving benefits.

Thermaspray and Plasma Coatings
Thermaspray is a formal licensee of Plasma Coatings and has made a substantial investment in bringing the technology to South Africa.

“With Thermaspray’s long history as an applicator of thermal spray coatings in South Africa, it made sound business sense to extend our capabilities,” says Lourens.

As a result, Thermaspray partnered with Plasma Coatings USA to enable it to apply the necessary metals and polymers. Plasma Coatings has 45 years of experience in coating technology, with plants in Wisconsin, Tennessee and Texas, in the US, as well as in Shanghai, China.